Propeller



Nov. 2, 1937. L. KAISER 2,098,100

PROPELLER Filed Nov. 15, 1933 2 She'ets-Sheet 1' H 2 2 F/Q. 1

2/ //v VE NTOR F/qa 1 2m wig/ ag -NOV. 2, 1937'. L KAISER 2,098,100

BROPELLER Filed NOV. 13, 1953 2 Sheets-Sheet 2 Patented Nov. 2, 1937 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to variable pitch propellers primarily for air-craft use.

An object of the present invention is to provide simple and improved mounting means for the propeller blades which will adequately sustain the centrifugal forces as well as the air loads imposed thereon, which will permit free pitch-varying .adiiwtment oi the blades, and which will permit prompt and independent removal of individual ,blades for replacement or repair.

Another object is to provide simple and improved means for regulating and controlling the pitch of the blades.

Another object is to provide simple and effective means for securely locking the blades in any desired position of pitch-varying adjustment.

Other more specific objects and advantages will appear, expressed or implied, from the following description of an illustrative embodiment of the present invention.

The present application is a continuation in part of my abandoned application S. N. 641,858 filed Nov. 9, 1932.

In the accompanying drawings;-

Figure 1 is a fragmentary front elevation of a propeller hub equipped with blade mounting and control means constructed in accordance with the present invention.

Fig. 2 is a top elevation, partly in longitudinal section, of the device shown in Fig. i.

Fig. 3 is a transverse sectional view taken substantially along the line 3-3 of Fig. 1.

Fig. 4 is a side elevation of one of the blade looking elements shown.

Fig. 5 is a sectional view illustrating particularly the blade locking clutch shown in elevation in Fig. 2.

Fig. 6 is a sectional view taken substantially along the lineB-G of Fig. 5.

Fig. 7 is a view in elevation of the clutch. control mechanism partly shown in section in Fig. 5.

Fig. 8 is a view in elevation of the clutch.

The propeller selected for illustration comprises a one-piece huh I, internally splined for mounting upon a propeller shaft in the usual manner, and having a plurality of hollow sleevelike members radiating therefrom for receiving form continuous raceways for sets of balls 8 confined the ein. The balls 8 coact with the grooves to securely hold each blade against longitudinal displacement and to adequately support the same against the air loads imposed thereon. The balls however permit each propeller blade to turn freely about its longitudinal axis in a manner to vary the pitch of the blade.

The balls 8 are admitted to the grooves through external ports, one of which is shown at 9 in Fig. 1 communicating with a groove 6, the ports being normally closed by plugs l0 screwed or otherwise removably fixed therein. Whenever it is desired to remove one of the propeller blades, it is a simple matter to release the same by removing the plugs l0 and permitting the balls 8 to discharge by gravity through the ports 9.

In the propeller shown, the pitch of each blade is regulated and controlled primarily by a ring 3 surrounding a reduced portion of the blade holder and axially movable thereon toward and from the central. huh I. Annular shoulders 5 at the ends of the reduced portion limit the movement of each ring. A plurality 'of balls 20, seated in sockets 2| formed internally of each ring, project through longitudinal guide slots i0 in the blade supporting member, and engage inclined cam grooves 22 in the blade shank 2, so that the shank 2 rotates in its support in response to axial movement of the ring 3.-

To facilitate assembly, the ring 3 is divided, as at l2, to form two half sections, releasably but securely fixed together by appropriate means, such as screws l3.

The arrangement is such that, during rotation of the propeller, the control ring 3 of each blade is urged outwardly by centrifugal force, and the balls 20, reacting to this outward thrust and coacting with the cam grooves 22, urge each blade to rotate in such direction as to vary the pitch thereof. The blades are so formed that the air load thereon urges them to rotate in the oppo-- site direction, with the result that the pitch varies in accordance with changes in the rotative speed of the propeller.

In order to synchronize and coordinate the pitch of the blades, suitable mechanical connections are preferably provided between the individual control rings 3. In this instance a link I, connected with each ring 3, is also connected with a center ring l5, freely rotatable upon the front end It of the propeller hub I. The ring i5 is retained on the hub by suitable means, such as a ring l8 releasably secured to the end of the hub. The ring I! is shown provided with gear teeth ll through which it may be actuatedor controlled. if desired.

Under some conditions oi operation it may be desired to securely lock the blades in any posinotches IA formed in the blade support.

An alternative form of blade locking means is shown in Figs. 2 and 5 to 8. It comprises a clutch ring 23 having clutch teeth II for interlocking engagement with mating teeth "A formed in the inner end of a blade shank I. The ring 28 is mounted for axial adjustment within a ring 24 anchored by pins 31 within the blade support. Balls 2! engaged in mating grooves 28 in the rings 23 and Il securely hold the clutch ring ll against rotation. The clutch ring 23 is yieldably retained in advanced position with its teeth 2| engaged with the blade teeth A by appropriate means such as springs 2|.

. Each clutch ring II is operated and controlled by a rod 3| which extends through slots 82,

formed in the clutch, and into a control collar 38 at the rear end of the propeller hub. The collar 88 rotates with, but is axially movable with respect to the hub I. A non-rotating control ring 34, loosely engaged behind the collar 3. is provided with control rods ll by which the ring 84 and collar 38 may be actuated to shift the rod 3| lengthwise. The rod Si is provided with a cam lug 80 which, when the rod II is thus shifted,

reacts against therear endofslot it ina direction to withdraw the clutch teeth II from teeth "A and thus render each propeller blade free to rotate and thus change its pitch.

The rods 38, ring I4, and collar 80 connected in the manner described makes possible a distant control of the clutch 28 while the propeller is in motion.

Various changes may be made in the embodiment of the invention hereinabove specifically described without departing from or sacrificing the advantages of the invention as deiined in the appended claims.

I claim:-

1. In a propeller the combination of a hub. hollow members projecting therefrom, a propeller blade rotatably mounted in each of said members, a ring encircling each oi! said members and movable axially thereof, a slot in each of said members, a non-parallel groove in each of said blades, and a ball engaged in said slot and groove and movable with said ring to rotate the associated blade.

2. In a propeller the combination of a hub, hollow members projecting therefrom, a propeller blade having a supporting shank rotatably mounted in each of said members, a clutch within each of said members, said clutch including a toothed element normally engaged with the associated shank to lock the same against rotation and movable axially thereof to release the latter. and control means extending from said propeller for operating said clutch elements to thereby release the shank.

LAWRENCE KAISER. 

